1. Field of the Invention
The present invention relates to a semiconductor device having improved heat dissipation, a method for manufacturing the same, and a semiconductor device mounting structure.
2. Description of Related Art
Along with an increase in the level of integration of integrated circuits and progress in size reduction of semiconductor elements in recent years, demand is growing for mounting techniques that can be employed to connect terminals arranged at narrow pitches. As the mounting structures that can satisfy this demand, TAB (Tape Automated Bonding), which is utilized for TCPs (Tape Carrier Packages), COG (Chip On Glass), which utilizes an anisotropic conductive film (ACF), COF (Chip On Film) and BOF (Bump On Film) are known.
These mounting structures have a basic configuration in which a protruding electrode called a bump is formed, using Au or solder, on each electrode pad of a semiconductor element, and the bumps on the semiconductor element are bonded at the same time to a metal wiring formed on a resin tape or glass substrate. However, in the case of BOF (Bump On Film), the protruding electrodes are formed on the metal wiring of a resin tape, and the electrode pads of the semiconductor element are bonded at the same time to the protruding electrodes.
The power consumption per unit volume of integrated circuits that employ the above-described mounting techniques is increasing along with an increase in the level of integration of integrated circuits, and therefore some semiconductor devices including such integrated circuits adopt measures against heat generation (see JP H10-41428A, for example).
FIG. 20 is a cross-sectional view illustrating the configuration of a semiconductor device that employs TAB as the mounting structure and takes measures against heat generation. On the main surface (i.e., the surface having the circuit forming region, the upper surface in FIG. 20) of a semiconductor element 101, protruding electrodes 102 are formed. A conductive wiring 104 patterned on a wiring board 103 is connected electrically to the protruding electrodes 102. The connected portions between the conductive wiring 104 and the protruding electrodes 102, and the main surface of the semiconductor element 101 are covered with a sealing resin 105. Further, an organic insulating material 111, such as polyimide or epoxy resin, for example, is provided on one of the surfaces of the wiring board 103, so as to cover an extending portion of the conductive wiring 104.
In a heat dissipating member 107, a recessed portion 110 is formed, and the semiconductor element 101 is disposed in the recessed portion 110. A filing material 106 is filled in the recessed portion 110 on the side that faces the back surface (the lower surface in FIG. 20) that is opposite to the main surface of the semiconductor element 101. This causes the back surface of the semiconductor element 101 to connect to the inner wall surface of the recessed portion 110 of the heat dissipating member 107 via the filling material 106.
Also, the conductive wiring 104 that is connected to the protruding electrodes 102 for grounding of the semiconductor element 101 is connected electrically to the heat dissipating member 107 via a conductive screw 108. Furthermore, the wiring board 103 and the heat dissipating member 107 are attached to each other with double-sided tape 109.
With this configuration, the heat generated at the main surface during operation of the semiconductor element 101 is transmitted from the back surface of the semiconductor element 101 through the filling material 106 to the heat dissipating member 107, where the heat is released into the air.
In addition, because a signal to the ground terminal from the semiconductor element 101 is transmitted from the protruding electrodes 102 through the conductive wiring 104 and the conductive screw 108 to the heat dissipating member 107, sufficient grounding can be effected, reducing noise and EMI (electromagnetic interference).
However, conventional semiconductor devices as shown in FIG. 20 have the problem that when the area of the wiring board 103 on which the conductive wiring 104 is formed is reduced for decreasing a size of the devices, the size of the heat dissipating member 107 also needs to be reduced, lowering the heat dissipation efficiency.